Special Weather Statement, NWS Blacksburg, VA

Area Forecast Discussion
National Weather Service Blacksburg VA
140 PM EDT Tue Jun 13 2017

.SYNOPSIS...
Strong High Pressure centered along the southeast Atlantic
coast will provide summer-like weather with very warm, hazy,
and humid conditions. Increasing moisture will lead to a daily
threat of showers and thunderstorms.

&&

.NEAR TERM /THROUGH TONIGHT/...
As 938 AM EDT Tuesday...

Convection associated with upper low/shortwave developed across
West Virginia this morning similar to what yesterday NAM
indicated. Storms at this time have been slow moving and back
building to our west. With the higher pwats values around 1.5
inches and mean wind less than 15 kts, some of these storms
could contain heavy rains. With Day One convective outlook
highlighting general thunderstorms for forecast area, we will
still have to monitor for pulse severe thunderstorms in the east
with wind potential as modified morning rnk 12z sounding showed
healthy dcapes.

High pressure centered off the southeast Atlantic coast will
continue a warm moist southwesterly flow of air across the
region. Increasing CAPE today will result in scattered to
numerous shower and thunderstorm coverage anticipated. Tried to
shape the timing with earliest convection over the ridges, then
it travels eastward into piedmont during the afternoon and
evening hours. For this morning updated modified temperatures
with latest surface obs and leaned to glamp. In general, running
a little warmer on temperatures this morning into this
afternoon. More adjustments as the day progress with more active
day expected.

AS of 500 AM EDT Tuesday...

High pressure centered just off the southeast Atlantic coast
will provide a warm moist southwesterly flow of air across the
region. Forecast soundings indicate increasing CAPE with
scattered to numerous shower coverage anticipated for the next
several days.

For today, weak twist in the water vapor imagery is centered
over the forecast area. This shortwave feature is caught within
the upper ridge, and will provide ample lift for scattered to
numerous showers and thunderstorms. HiRes models suggest little
cap compared to yesterday with activity blossoming before noon
per increasing mid-level instability. Potential exists for slow
moving pulse storms as SBCAPE increases into the 2000-2500 j/kg
range for this afternoon. Forecast PWATs AOA 1.5 and mean wind
less than 15 kts suggest potential for heavy rainers where
storms do occur.

Temperatures today will be very similar to yesterday with highs
of 85 to 92 for the Roanoke Valley and east of the Blue Ridge
and 75 to 84 across the higher elevations and mountain valleys.

A few lingering showers may persist tonight, but overall
coverage should decrease dramatically after loss of daytime
heating. High dewpoints will promote a muggy feel to the air
with readings in the 60s to near 70. These elevated dewpoints
will also maintain warm overnight lows with minimum temperatures
dipping no lower than the dewpoint readings.

&&

.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
As of 500 AM EDT Tuesday...

Looking to Wednesday, scattered showers and thunderstorms will again
be in the forecast due to the combination of abundant moisture
lifting northward along the Appalachian chain and strong daytime
heating. Convection is expected to initially begin along the ridges
during late morning and gradually spread during the afternoon, and
culminate with possibly a broken line of thunderstorms moving
southeast across the Piedmont during the evening as an upper level
disturbance moves in from the Ohio River Valley. Despite weak upper
level support, strong surface heating will push CAPE values during
the afternoon in the 1500 to 2000 J/kg range, which will support
pulse-variety strong to severe storms, capable of producing
localized wind damage, in addition to hail. Light winds aloft will
also promote slow storm movement, making for prolonged periods of
heavy rain for some locations.

Passage of the upper level disturbance and associated thunderstorms
will help draw a cold front southward across the Piedmont late
Wednesday and early Thursday, with winds eventually shifting more
east-southeasterly by late morning as low pressure passes north of
the Great Lakes. The upslope flow combined with instability aloft
will support scattered on and off showers and thunderstorms across
the mountains/foothills into the evening. Widespread cloud cover and
scattered rainfall will support cooler afternoon high temperatures
ranging from the mid 70s to the low 80s, and therefore stuck closer
to the cool side of model guidance for the temperature forecast.

Weather forecast models indicate that the front draped across the
center of our region will drift northward on Friday/Friday night,
but will still provide the focus for continued scattered on and off
showers and thunderstorms areawide, with coverage increasing by mid
Friday morning. Given weather forecast models trend of lifting warm
fronts northward too quickly across the mid Atlantic, again stuck
close to the cooler side of model guidance for Friday afternoon
highs.

&&

.LONG TERM /SATURDAY THROUGH MONDAY/...
As of 500 AM EDT Tuesday...

Our region will fall under the northern periphery a large upper
level southeast U.S. ridge for most of the long term period, with
heights beginning to fall late in the period as an upper trof moves
into the Great Lakes into the Ohio Valley, with the GFS slightly
faster with the approach of a cold front associated with this
feature Monday.

Surging 850mb temps will result in above normal temperatures
Saturday-Monday and a continued chance for afternoon and evening
storms. Depending on the timing of the arrival a cold front late in
the long term period...storms could be more organized by Monday.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
As of 140 PM EDT Tuesday...

High pressure will remain along the southeast Atlantic Coast
this afternoon into Wednesday. This will support mainly VFR
conditions through the TAF valid period with the exception of
brief periods of scattered MVFR due to diurnally driven deep
convection and patchy fog/haze.

MVFR/IFR scattered deep convection in the mountains will move
east this afternoon and drift east into the piedmont before
dissipating near sunset. A few showers will may linger overnight
mainly in the west. Scattered MVFR convection will continue
Wednesday as backdoor cold front approaches from the northern
Virginia.

High confidence in ceilings, visibilities and winds during the
taf period.

Extended Aviation Discussion...

Deep Gulf moisture will spread north and northeast from the
Midsouth and Southeast U.S. into the Mid-Atlantic region through
midweek. Expect an increase in diurnally driven showers and
thunderstorms, with scattered to numerous coverage is
anticipated Wednesday afternoon as a backdoor cold front
approaches from northern VA. This front will linger in the area
Wednesday night through Thursday before retreating back to the
north. A stronger cold front and upper-level disturbance will
arrive from the west late in the week. Therefore, expect
scattered to numerous convective activity, mainly during the
afternoon and evenings, throughout the week beginning Wednesday.
Wed-Fri offer the best opportunities for widespread showers and
thunderstorms and extended periods of sub-VFR ceilings and
visibilities. In addition, radiational late night/early morning
fog will be on the increase once daily showers and thunderstorms
commence, hence Wednesday morning onward. Unsettled weather
continues into the weekend.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.

&&

SYNOPSIS...PM
NEAR TERM...KK/PM
SHORT TERM...NF
LONG TERM...PH
AVIATION...KK/PM

Hazardous Weather Outlook
National Weather Service Blacksburg VA
629 AM EDT Tue Jun 13 2017

NCZ001>006-018>020-VAZ007-009>020-022>024-032>035-043>047-058-059-
WVZ042>044-507-508-141030-
Ashe-Alleghany NC-Surry-Stokes-Rockingham-Caswell-Watauga-Wilkes-
Yadkin-Tazewell-Smyth-Bland-Giles-Wythe-Pulaski-Montgomery-Grayson-
Carroll-Floyd-Craig-Alleghany VA-Bath-Roanoke-Botetourt-Rockbridge-
Patrick-Franklin-Bedford-Amherst-Henry-Pittsylvania-Campbell-
Appomattox-Buckingham-Halifax-Charlotte-Mercer-Summers-Monroe-
Eastern Greenbrier-Western Greenbrier-
629 AM EDT Tue Jun 13 2017

This Hazardous Weather Outlook is for north central North Carolina,
northwest North Carolina, central Virginia, south central Virginia,
southwest Virginia, west central Virginia and southeast West
Virginia.

.DAY ONE...Today and tonight.

There is a low probability for widespread hazardous weather. However,
a few strong storms are likely this afternoon. Slow movement will
also lead to locally heavy rain and potential for poor drainage
flooding.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Strong storms are possible Wednesday, some marginally severe with the
potential for damaging wind and large hail.

Thunderstorms Thursday and into the weekend may also pulse into
locally strong to marginally severe levels. However, the probability
of widespread hazardous weather is low at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

Special Weather Statement
National Weather Service BLACKSBURG VA
1148 AM EDT TUE JUN 13 2017

VAZ010-011-013-WVZ042>044-131630-
Giles-Pulaski-Bland-Mercer-Summers-Monroe-
1148 AM EDT TUE JUN 13 2017

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT
NORTHWESTERN PULASKI...GILES...NORTHEASTERN BLAND...SUMMERS...MERCER
AND WESTERN MONROE COUNTIES...

At 1147 AM EDT, radar indicated strong thunderstorms were located
along a line extending from Sandstone to Dunns to near Coaldale.
Movement was southeast at 25 mph.

Wind gusts up to 50 mph and hail up to dime size are possible with
these storms.

Locations impacted include...
Princeton...
Pearisburg...
Hinton...
Narrows...
and Pembroke.

Torrential rainfall is also occurring with these storms, and may
cause localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

LAT...LON 3751 8041 3726 8057 3709 8085 3742 8132
      3742 8128 3745 8130 3750 8126 3751 8121
      3757 8120 3760 8114 3759 8109 3764 8107
      3772 8097 3770 8091 3767 8090 3768 8088
      3774 8092 3777 8089 3781 8093 3784 8087
TIME...MOT...LOC 1547Z 319DEG 20KT 3777 8090 3752 8104 3739 8132

Loconto

Special Weather Statement
National Weather Service BLACKSBURG VA
1229 PM EDT TUE JUN 13 2017

VAZ012-013-016-017-131715-
Pulaski-Floyd-Wythe-Carroll-
1229 PM EDT TUE JUN 13 2017

...A STRONG THUNDERSTORM WILL AFFECT
SOUTH CENTRAL PULASKI...SOUTHWESTERN FLOYD...EAST CENTRAL WYTHE AND
NORTHEASTERN CARROLL COUNTIES...

At 1229 PM EDT, a strong thunderstorm was located over Allisonia,
moving southeast at 25 mph.

Wind gusts up to 50 mph and dime size hail are possible with this
storm.

Locations impacted include...
Hillsville...
Willis...
Allisonia...
Patterson...
and Indian Valley.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

Persons in campgrounds should consider seeking sturdy shelter until
this storm passes.

LAT...LON 3694 8088 3703 8072 3680 8039 3669 8067
TIME...MOT...LOC 1629Z 317DEG 20KT 3693 8071

Loconto

Special Weather Statement
National Weather Service BLACKSBURG VA
105 PM EDT TUE JUN 13 2017

VAZ013-014-017-131800-
Pulaski-Floyd-Montgomery-
105 PM EDT TUE JUN 13 2017

...AN AREA OF STRONG THUNDERSTORMS WILL AFFECT
NORTHEASTERN PULASKI...CENTRAL FLOYD AND SOUTHWESTERN MONTGOMERY
COUNTIES AND THE CITY OF RADFORD...

At 104 PM EDT, strong thunderstorms were clustered over Dublin,
moving east at 10 mph.

Winds in excess of 40 mph and dime size hail are possible with this
storm.

Locations impacted include...
Christiansburg...
Radford...
Pulaski...
and Dublin.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

If you are on or near the northern half of Claytor Lake, get out of
the water and move indoors or inside a vehicle. Remember, lightning
can strike out to 10 miles from the parent thunderstorm. If you can
hear thunder, you are close enough to be struck by lightning. Move
to safe shelter now! Do not be caught on the water in a thunderstorm.

LAT...LON 3706 8078 3720 8073 3720 8071 3722 8067
      3718 8029 3692 8039
TIME...MOT...LOC 1704Z 286DEG 10KT 3713 8067

Loconto

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BLACKSBURG VA
203 PM EDT TUE JUN 13 2017

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0110 PM     HAIL             1 SW DUBLIN             37.11N 80.71W
06/13/2017  E0.75 INCH       PULASKI            VA   CO-OP OBSERVER

&&

SK

Special Weather Statement
National Weather Service BLACKSBURG VA
207 PM EDT TUE JUN 13 2017

VAZ014-017-033-131900-
Franklin-Floyd-Montgomery-
207 PM EDT TUE JUN 13 2017

...A STRONG THUNDERSTORM WILL AFFECT
NORTHEASTERN FLOYD...CENTRAL FRANKLIN AND SOUTHEASTERN MONTGOMERY
COUNTIES...

At 206 PM EDT, a strong thunderstorm was located over Check, moving
east at 15 mph.

Wind gusts up to 50 mph and nickel size hail are possible with this
storm.

Locations impacted include...
Rocky Mount...
Boones Mill...
Copper Hill...
Ferrum...
and Burnt Chimney.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

LAT...LON 3697 8028 3716 8023 3715 8018 3711 8018
      3711 8017 3712 8012 3713 8012 3714 8011
      3715 8011 3711 7979 3688 7987
TIME...MOT...LOC 1806Z 284DEG 11KT 3706 8017

Loconto

Special Weather Statement
National Weather Service BLACKSBURG VA
217 PM EDT TUE JUN 13 2017

VAZ032-043-131900-
Henry-Patrick-
217 PM EDT TUE JUN 13 2017

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT
SOUTHWESTERN HENRY AND PATRICK COUNTIES...

At 217 PM EDT, radar indicated strong thunderstorms were located
along a line extending from near Woolwine to near Stuart to near
Collinstown. Movement was southeast at 10 mph.

Wind gusts up to 50 mph and dime size hail are possible with these
storms.

Locations impacted include...
Stuart...
Spencer...
Bassett...
Woolwine...
and Critz.

Torrential rainfall is also occurring with these storms, and may
cause localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

LAT...LON 3656 8047 3670 8036 3684 8031 3684 8030
      3686 8029 3686 8028 3679 8004 3678 8003
      3678 8001 3676 7994 3661 7998 3654 8003
TIME...MOT...LOC 1817Z 294DEG 10KT 3681 8026 3667 8027 3662 8034

Loconto